Flying Blind: TPE for Acute Kernicterus in Crigler-Najjar Syndrome

Introduction

One of the most humbling experiences in medicine is when a consult comes in and you realize the textbook has nothing for you. I had one of those recently — a 21-year-old with Crigler-Najjar syndrome type 1 and chronic kernicterus, averbal at baseline, who presented to an outside hospital with an infection and altered mental status. Her at-home bili lights were unavailable, and her bilirubin climbed from a baseline of around 24 to 32 mg/dL. She was transferred for ICU-level care and started on continuous phototherapy, which brought her bilirubin down from 32 to 29 — but her mental status didn’t budge. The concern was acute-on-chronic kernicterus, and now she was being transferred to us for therapeutic plasma exchange.

Lord almighty, did I have a hard time coming up with a game plan.

Crigler-Najjar Syndrome: A Primer

For the uninitiated, Crigler-Najjar syndrome type 1 is a rare genetic disorder in which the enzyme responsible for conjugating bilirubin in the liver — UGT1A1 — is absent or nonfunctional. Without conjugation, unconjugated bilirubin accumulates in the blood. Unlike the common, transient jaundice seen in newborns, this is a lifelong condition. The mainstay of treatment is phototherapy, often for 10 to 16 hours daily, which isomerizes bilirubin into a water-soluble form that can be excreted without conjugation. The only definitive cure is liver transplantation, though gene therapy trials are underway. When bilirubin rises above a patient’s baseline — due to infection, fasting, or loss of access to phototherapy — the risk of acute bilirubin encephalopathy, or kernicterus, becomes very real.

What the Literature Says (and Doesn’t Say)

So, does therapeutic plasma exchange (TPE) have a role in acute kernicterus for Crigler-Najjar patients? I went to the literature to find out. What I found was… underwhelming.

TPE is not listed as a primary indication in the ASFA guidelines for Crigler-Najjar syndrome. The evidence that does exist consists of scattered case reports and case series, and in every single one, plasmapheresis is treated as an afterthought — mentioned almost in passing as something that was done during a crisis, without rigorous evaluation of its contribution to the outcome.

A 10-year-old with CN1 who developed kernicterus during streptococcal pharyngitis was treated with plasmapheresis, intensive phototherapy, and antibiotics, and recovered without neurologic sequelae.

A 23-year-old man with CN1 who developed acute hepatitis from infectious mononucleosis received plasmapheresis to prevent neurological decline.

A 2-month-old with a bilirubin of 30 mg/dL and signs of encephalopathy underwent plasmapheresis and urgent liver transplantation.

Two 17-year-old boys with bilirubins in the 30s received intermittent plasmapheresis over a prolonged hospitalization. In none of these reports is there a standardized protocol.

In none of them is TPE the focus of the study. It’s always a side note.

Borrowing from the Acute Liver Failure Literature

That left me with some very practical questions and very few answers. What exchange volume should I use? What replacement fluid? How often? The Crigler-Najjar literature doesn’t say. So I looked to the closest analogy I could find: the acute liver failure literature.

In acute liver failure (ALF), high-volume plasma exchange (HVPE) has become a first-line therapy, based on a landmark 2016 randomized trial by Larsen and colleagues showing improved survival. HVPE in that context is defined as 8 to 12 liters of exchange, or about 15% of ideal body weight, which works out to roughly 2.5 to 3 plasma volumes. The replacement fluid is fresh frozen plasma, because ALF patients have severe coagulopathy and need factor replacement. A subsequent 2022 trial showed that even standard-volume plasma exchange — 1.5 to 2 plasma volumes — was effective and potentially safer with respect to cerebral edema.

But here’s the critical difference: in ALF, the liver can potentially recover. In Crigler-Najjar, the enzyme deficiency is permanent. Bilirubin production continues at roughly 4 to 5 mg/dL per day, and studies have shown that bilirubin rebounds within 24 hours after plasma exchange.

TPE in this context is a temporizing measure at best — buying time while you maximize phototherapy and, if indicated, arrange for transplant evaluation.

My Approach

I also had to consider the replacement fluid question carefully. The ALF literature uses FFP because those patients need clotting factors. My patient didn’t have liver synthetic dysfunction — her liver makes everything except functional UGT1A1. What she needed was bilirubin removal, and albumin is the primary carrier of unconjugated bilirubin in the blood. On the other hand, some FFP in the replacement fluid provides additional albumin and maintains oncotic pressure. I ultimately decided on a one-time TPE with a 50/50 mix of albumin and plasma — a pragmatic decision born more from first principles than from evidence, because the evidence simply doesn’t exist for this specific scenario.

I also recommended maximizing phototherapy — exposing as much skin surface area as possible and using as many bili light devices as they could get their hands on. Phototherapy remains the workhorse of bilirubin management in CN1, and TPE without concurrent aggressive phototherapy is unlikely to make a meaningful dent.

When Evidence Runs Out

The broader point here is one that I think resonates with anyone who practices in a niche or rare-disease space: sometimes the literature leaves you on your own. You can search every database, pull every case report, and still end up making decisions based on pathophysiology, first principles, and clinical judgment rather than evidence-based protocols. That’s not a comfortable place to be, but it’s an honest one.

A Call for Better Evidence

For Crigler-Najjar patients in acute crisis, I think there’s a real need for better evidence on the role of TPE. What volume? What fluid? What schedule? Does it actually change outcomes, or does it just change numbers on a screen? These are questions that case reports can’t answer.

Given the rarity of the condition, a multi-center registry or collaborative case series with standardized TPE protocols would be a reasonable starting point.

In the meantime, if you get this consult, know that you’re not going to find a protocol waiting for you. You’re going to have to reason through it.

And if you come up with something better than what I did, I’d love to hear about it.